Exotoxins

Question 1

Exotoxins

Answer 1

• mainly produced by G+ bacteria, but can also be produced by G- bacteria
• Selected/released from the bacteria and travels to the target organ through blood stream
• They are polypeptides
• denaturated by heat, acid
• Have high biological activity
• highly specific action
• Strongly antigenic
• Can form toxoid

Question 2

Extracellularly acting exotoxins

Answer 2

• membrane damage
• pore formation (hemolysins and leukocidins) –> loss of nutrients –> cell death
• Phospholipases cleaves PL in the cell membrane

Question 3

Intracellularly acting exotoxins

Answer 3

- A+B toxin: 
A: enzymatic activity of the toxin
B: cell surface binding
Inhibition of protein synthesis
 - Overproduction of mediators (ACH--> tetanus)
 - Hypersecretion (Cholera toxin)

Question 4

Some divide according to site of action:

Answer 4

• Neurotoxins
• Enterotoxins
• Leukocidin
• Hemolysin
• Cytotoxins
• Lethal toxins